1. Technical Field
The present disclosure relates to diffusion sheets having a sub-wavelength gating and particularly to a backlight module for liquid crystal display devices employing such a diffusion sheet.
2. Description of Related Art
Direct type backlight modules in an LCD display device usually include light sources placed under the LCD panel and a diffuser located between the LCD panel and the light sources. The light emitted by the light sources propagates through the diffusion sheet and is diffused by the diffusion sheet, and then passes through a light emitting surface of the diffusion sheet. However, some of the lights may be entirely reflected and cannot pass through the light emitting surface because of a total internal reflection, so that light utilization efficiency is deceased.
Therefore, it is desirable to provide a new kind of backlight module to resolve the above shortcomings